Teledyne RD Instruments

yakzephyrAI and Robotics

Nov 24, 2013 (3 years and 10 months ago)

60 views

Teledyne

RD Instruments




Leaders in Acoustic Doppler Current
Profilers

and Doppler Velocity Logs

Measuring Water in Motion and Motion in Water

Communications

Technologies

Bertinoro 2009

Measuring Waves Accurately
Workhorse Waves Array ADCP

Darryl Symonds

Director of Marine Measurements Product Lines

Teledyne RD Instruments



Waves Measuring Techniques

1.
Pressure Sensor Array

2.
Triplet Processing

3.
Orbital Velocity Array

Pressure Sensor for Waves

1.
Use a single pressure sensor to measure
the change in the water surface height;
provides non
-
directional waves data
(Wave Height and Period)

2.
Use an array of pressure sensors to
measure the change in the water surface
height at several locations at once;
provides direction waves data (Wave
Direction)

Triplet Processing for Waves

Uses 3 parameters to provide waves data

1.
Measure changes in the height of the water to
provide non
-
directional waves data (Wave
Height and Period)

2.
Measure water velocity to provide directional
waves data

Techniques

1.
PUV


Pressure + U/V Horizontal Velocity Vectors

2.
UVW


Vertical
Vel

+ U/V
Horizontal Velocity Vectors

3.
SUV


Vertical Range
+ U/V Horizontal Velocity Vectors


Orbital Velocities for Waves


Measures the orbital velocities below the
surface at multiple layers to provide 4
-
20
independent measurements of the orbital
velocity created by a passing wave

Waves energy propagation

Orbital Wave Energy is
flattened due to the
bottom

Energy of short
waves decays
with depth

RDI ADCP Waves
Measurements Techniques

WH
Sentinel

Monitor
ADCP

NEMO

WH
Horizontal

ADCP

RDI Sentinel ADCP Waves

WH
Sentinel

Monitor
ADCP

Measurements:


Current Profile


Echo Intensity


U/V Velocity


Vert

Velocity


Pressure


Surface Track


Triplet Processing


PUV/UVW

P

P

P

Pressure = Non Directional Wave Data: Hs,
Tp


UV Velocity Bin = Directional Wave Data:
Dp


UVW Velocity Bin = Non Directional and Directional Wave Data: Hs,
Tp
,
Dp


Surface Tracking


4 Beams

4 Beam Array = Non Directional: Hs,
Tp

UV Velocity Bin = Directional Wave Data:
Dp


Orbital Waves
Processing

Acoustic Doppler Solutions

4
-
20 Independent
Orbital Fluctuation
Sensors


Directional Spectrum
with IMLM

Data Provided by the WH Sentinel
ADCP Waves System

Simultaneous Currents and Waves

Current Profile Information

-
East/North/Vertical Velocity

-
Error Velocity

-
Correlation

-
Echo Intensity

-
Percent Good

Data Provided by the WH Sentinel
ADCP Waves System

Simultaneous Currents and Waves

Wave Information

-
Processed Parameters (Height, Period,
Direction)

-
Non Directional Spectra (3 methods;
Orbital, Surface Track, and Pressure)

-
Directional Spectra

Height, Period, Direction, Tides

Time Series

TIDES

Peak PERIOD

Peak DIRECTION

Significant Wave HEIGHT

High Frequency Wave Energy
-0.2
0
0.2
0.4
0.6
0.8
1
0
0.2
0.4
0.6
0.8
Hz
m/root(Hz)
ADCP Surface Track
ADCP Vel Spec
ADV
Non Directional Spectrum

(Wave Height Spectrum)

Surface
Tracking

Orbital
Array
Velocity

Pressure
Sensor



Triplet

(PUV)

Narrow

Band Array

RDI Vertical

ADCP Array

Frequency

NA

600kHz

600kHz

# Sensors

3

3

12

Signal Processing

NA

Narrow

Band (U/V)

BroadBand

Bin Size (meters)

NA

2

0.7

Measurement

Precision (cm/sec)

1.0

5.7

3.9

Array Aperture (m)

Assumes 20 meter

depth

Single

Point

10

7

Comparing
Methods

Comparing Directional
Resolution

NarrowBand

Array

Triplet (PUV
)

RDI
VADCP
Array

Summary of the WH Sentinel ADCP
Waves System


RDI’s ADCP Wave Array provides several instruments
at the same time in one package


current profiling AND


directional wave gauge AND


water level device


Directional Wave Analysis


array type measurement refines direction resolution


Reveals and corrects for bias due to wave
-
current
interaction


3 independent methods collected for comparison
and quality assurance

RDI ADCP Waves
Measurements Techniques

WH
Horizontal

ADCP

Measurements:


Horizontal Current
Profile


Echo Intensity


U/V Velocity Array


Pressure


Orbital Waves
Processing


Horizontal ADCP is at
a single layer below
the surface


Directly measures the
entire wave field.


Directional Spectrum
with IMLM




Triplet

(PUV)


Narrow

Band

Array

RDI

Vertical

ADCP

Array

RDI

Horizontal

ADCP

Frequency

NA

600kHz

600kHz

300kHz

# Sensors

3

3

4
-
20

15

Signal Processing

NA

NarrowBand

BroadBand

BroadBand

Bin Size (meters)

NA

2

0.7

8

Measurement

Precision (cm/sec)

1.0

5.7

3.9

1.1

Array Aperture (m)

Assumes 20 meter

depth

Single

Point

10

7

140

Comparing Systems


Real Time Measurements in Ports, Navigation
Channels, and Oil Platforms


Improves Directional Wave Spectra


Improves Long Wave Measurement
Performance


Lower system reduced
Maintenance
Cost

Summary of the WH Horizontal
ADCP Waves System

Waves Measuring Setup

1.
Which Processing Method?

2.
What is the Data Collection Interval?

3.
What about Real Time Data Collection?

Orbital Velocity Array Considerations

Benefits

Concerns

Collect

data sub surface

Must be a fixed bottom mount

Waves data

information is
collected near the surface

Selection of proper

depth
cells


Automatic

waves depth cell
selection

Must ensure the pressur
e
sensor is working correctly

Collect

s
imultaneous current

profiles and waves data

Power consumption for waves

pinging requires more batteries

Collect

data at
water

depths

5
-
80m

U
pper cutoff frequency lowered
as depth increases

“Compressed” waves data

allows for easier data output

The waves

packets are large


Surface Track Considerations

Benefits

Concerns

Collect

data sub surface

Must be a fixed bottom mount

Directly measure

the surface
height

Air

bubbles and high sediment
in the water column

Automatic

waves depth cell
selection

Must ensure the pressur
e
sensor is working correctly

Collect

s
imultaneous current

profiles and waves data

Power consumption for waves

pinging requires more batteries

Collect

data at
water

depths
10
-
80m

U
pper cutoff frequency lowered
as depth increases

“Compressed” waves data

allows for easier data output

The waves

packets are large


UVW Considerations

Benefits

Concerns

Collect

data sub surface

Must be a fixed bottom mount

In
-
directly measure

the surface
height

High frequency

changes are
attenuated at
depth

Collect

s
imultaneous current

profiles and waves data

Power consumption for waves

pinging requires more batteries

Collect

data at
water

depths
10
-
80m

U
pper cutoff frequency lowered
as depth increases

So which Method to Use?


Data for all 3 methods is collected by the
ADCP at the same time.


Each method can be separately processed
by the RDI software.


Compare results if all agree then use the
Orbital Velocity data


If there are differences verify if the Concerns
caused a bias and select the method that
does not have bias

Currents Only Ping Setup

10min
Ensemble

10min
Ensemble

10min
Ensemble

10min
Ensemble

10min
Ensemble

10min
Ensemble

Single Ping
Ensembles

Multiple Ping
Ensembles Evenly
Spaced in Time

Multiple Ping
Burst Ensembles

Currents Only Ensemble Setup

Burst Ping Ensembles

8 Pings/
Ens

* 6
Ens
/Hr =

48 Pings/hr

Burst Ping Ensembles

+ Burst Ensembles

2 Pings/
Ens

* 24
Ens
/Hr =

48 Pings/Hr

10 Min

10 Min

Waves Sampling Strategies

10min
Current
Ens.

10min
Current
Ens.

10min
Current
Ens.

10min

Current

Ens.

10min
Current
Ens.

10min
Current
Ens.

Waves Burst duration is
User Selectable,
min/typical 20mins

Pings for Current Ens.
within Waves burst are
shared with Wave Burst

Current Ens. Are User
Selectable typical
10mins (TE
Cmnd
)

Pings for Current Ens.
outside Waves burst
are at User Selected
Interval (TP
Cmnd
)

Pings for Waves Burst
are 2Hz

Waves Sampling Strategies

Waves Burst interval is User
Selectable:
-

min/typical 1 per hour
-

max 1 per 3 hours

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

10min
Ens.

Wave


Burst

Wave


Burst

RDI ADCPs AND REAL
TIME

COMUNICATIONS

Real Time Data Requirement

RDI ADCP Real Time Waves

NEMO

Advantages:


Remote Real Time
Currents and Waves

Processing


Use
Orbital Waves or
UVW
Processing


Allows low data
bandwidth applications


Stand alone or integrated



SeaBird Electronics
Inductive Modems


Teledyne Benthos
Acoustic Modems

RDI Integrated Real Time
Options

WH External
Battery Case

WH Sentinel
w/RDI NEMO

RDI WH with Integrated
NEMO and Internal/External
SBE IMM Integration Setup

Features:


All of the previous


WH Powers NEMO and IMM


Expandable Battery Integration for
30
-
365 Day Deployments


SBE Underwater
IMM with coupler
and cable mount.

RDI WH with External SBE IMM
Integration Setup

2700 lb. DW anchor
60 meters of
5
8
" Mooring Chain
X meters of
3
8
" Nilspin
Insulated mooring cable.

Seawater

Ground

Seawater

Ground

Anchor

Surface Buoy with Surface Modem

SBE IMM Coupler

RDI

WH ADCP
with IMM
Coupler

RDI WH with Internal SBE IMM
Integration Setup

SBE IMM Coupler

RDI WH ADCP

RDI WH with Internal SBE IMM
Integration Setup

Features:


WH synchronous or asynchronous with IMM


Real time data access


No interruption of asynchronous WH data


Stored data access through IMM 16KByte
Loop Recorder


Powered by single WH battery for 1year;
deployment duration depends on model and
user setup


Inductive Setup Considerations


Mooring Cable Diameter


Support 9.5mm(3/8”)


19.1mm(3/4“) diameter cables


Coupler spacers supplied to limit cable motion within
coupler


Power Consumption


Power consumption for RDI ADCP


Power consumption for IMM data access


Plan for IMM power consumption during other sensor
downloads


Data Format


ASCII or Binary data


Complete data or subset


Contacts

Main Office:

Teledyne RD Instruments, Inc.

14020 Stowe Drive

Poway, CA 92064

Main: +1
-
858
-
842
-
2600

www.rdinstruments.com



European Office:

Teledyne RDI Europe

5 Avenue Hector
Pintus

La
Gaude
, France

Main: +33
-
492
-
110
-
930


China Office:

Teledyne RD Technologies:

1206
Dongfang

Road,
Pu

Dong

Shanghai 20122

China

Main: +86
-
215
-
830
-
6939


Italy Representative:

Gianni Basini & Sandro Giordano

Communications Technology

Pzza Guidazzi 3

Cesena 97023 Italy

+39 0547 646561

gb@comm
-
tech.com

sg@comm
-
tech.com

www.comm
-
tech.com